Calculadora

Dim opera As ByteDim num1, num2 As DoublePrivate Sub cmdCero_Click()txtVisor.Text = txtVisor.Text + Str(0)End SubPrivate Sub cmdCinco_Click()txtVisor.Text = txtVisor.Text + Str(5)End SubPrivate Sub cmdCuatro_Click()txtVisor.Text = txtVisor.Text + Str(4)End SubPrivate Sub cmdDivision_Click()num1 = Val(txtVisor.Text)opera = 4txtVisor.Text = " "End SubPrivate Sub cmdDos_Click()txtVisor.Text = txtVisor.Text + Str(2)End SubPrivate Sub cmdIgual_Click()Resp = 0num2 = Val(txtVisor.Text)If opera = 1 ThenResp = num1 + num2End IfIf opera = 2 ThenResp = num1 - num2End IfIf opera = 3 ThenResp = num1 * num2End IfIf opera = 4 ThenIf num2 = 0 ThenMsgBox "Error... No puede dividirse por 0"Exit SubEnd IfResp = num1 / num2End IftxtVisor.Text = RespIf opera = 5 ThenResp = Sqr(num1)End IfEnd SubPrivate Sub cmdMultiplicacion_Click()num1 = Val(txtVisor.Text)opera = 3txtVisor.Text = " "End SubPrivate Sub cmdNueve_Click()txtVisor.Text = txtVisor.Text + Str(9)End SubPrivate Sub cmdOcho_Click()txtVisor.Text = txtVisor.Text + Str(8)End SubPrivate Sub cmdRaiz_Click()num1 = Val(txtVisor.Text)opera = 5txtVisor.Text = ""End SubPrivate Sub cmdResta_Click()num1 = Val(txtVisor.Text)opera = 2txtVisor.Text = " "End SubPrivate Sub cmdSeis_Click()txtVisor.Text = txtVisor.Text + Str(6)End SubPrivate Sub cmdSiete_Click()txtVisor.Text = txtVisor.Text + Str(7)End SubPrivate Sub cmdSuma_Click()num1 = Val(txtVisor.Text)opera = 1txtVisor.Text = " "End SubPrivate Sub cmdTres_Click()txtVisor.Text = txtVisor.Text + Str(3)End SubPrivate Sub cmdUno_Click()txtVisor.Text = txtVisor.Text + Str(1)End SubPrivate Sub Command1_Click()txtVisor.Text = ""num1 = 0num2 = 0Resp = 0End SubPrivate Sub Command2_Click()EndEnd SubPrivate Sub Form_Load()num1 = 0num2 = 0End Sub